Galvanic cell with automatic depolarization



sept. 2s, 1926. 1,601,036

H. D. NYBERG GALVANIC GELL WITH AUTOMATIC DEPOLARIZATION Filed May 25 1922 Patented Sept 28, ll

trs

HERMAN DOUGLAS NYBERG, QF NORRKOPING, SWEDEN.

GALVANIC CELL WITH AUTOMATIC DEPOLARIZATION.

Application led May 23, 1922, Serial No. 563,156, and in Sweden June 14, 1921,.

In the construction of galvanic cells with automatic gas depolarization it has been 1mpossible hitherto to provide acell with great efficiency, chiefly due to the diiiiculty o f pro- 5 curing a suiiiciently 4active depolar1zation.

In one kind of cells of the said type. before known, a central inner electrode of porous carbon, prepared in a special manner, is provided in an outer vessel, through which 1c carbon the gas depolarization takes place. To such an inner central carbon electrode, however, comparatively small dimensions must be given in respect of the outer vessel, which results in the contact surfaces of the' electrode with the air or any other gas as well as with the electrolyte being compara4 tively small and the gas depolarization, in consequence thereof, being rather slight. For that reason cells of the said type by a long way do not permit such a great load as with respect to the total size of the cell would be gained, if an effective gas depolari zation was effected.

For that reason stress must be laid upon the arranging of the carbon electrode in such manner, that it gets the greatest possible Contact surface with the depolarizing gas (air) as well as with 'the electrolyte. rlhis is effected, according te the vpresent invention, in the lirst place by arranging the carbon electrode as an outer vessel for the other parts constituting the cell.

Efforts in the said direction have been previously made, but have been unsuccessful due to the fact that the liquid electrolyte is forced by the hydrostatic pressure through the pores of the carbon, the depolarization being then rendered perfectly impossible (see German Patent No. 81.978, page l, column 2, lines 12 and i3). For the removing of the said disadvantage a. pastelilre electro-- lyte must be used according to the said patent, which by a percus cylinder of clay is separated from the outer carbon electrode. Consequently, in this case the carbon electrode does not constitute a vessel for the electrolyte but it is the porous clay cylinder which contains the same.

Thus, one has not succeeded in using really liquid electrolyte in cells,r in which the carbon electrode serves directly an outer vessel, the liquid electrelyte being, however, et the greatest importance for ;aintaining of a voltage as constnt as possible, owing to @35 the fact that the generated vions preducts of decomposition then get the opportunity of diffusing very easily from the electrodes respectively, in consequence whereof the original greatest voltage of the cell may be maintained more perfectly during the operation of the cell. This, however, isV impossible when pastelike electrolyte is used, because the diffusion then takes place with great difficulty.

According to this invention it is possible in galvanic. cells of. the type stated to use a carbon electrode, serving as an outer vessel, in combination even with a perfectly liquid electrolyte and thus to gain an eective, automatic gas depolarization, which in its turn renders possible the increasing of the efficiency of the cell in the greatest possible de- `aree, while a constant voltage is maintained. The said result is gained by the active walls of the outer carbon-vessel comprising two or more mutually coliering layers, located side by side, one of the said layers which is in contact with the electrolyte being wet by the same so that the electrolyte can penetrate into its pores, while the layer of carbon bordering upon said layer contains one or more substances which in the greatest possible degree can prevent the electrolyte from permeating the carbon electrode. The said penetrating of the electrolyte for a certain depth into the pores of the inner surface of the carbon is of the greatest importance owing to the considerable increasing of the` Contact surface between the electrode and the electrolyte which partly facilitates the transition. of the current partly results in the great quant-ities of depclarizing gas, which have penetrated into the pores of the carbon from the outside, entering into contactv with the great total surface of the electrolyte contained in the said pores, in consequence whereof the depolarizing operation becomes very effective. Thus, further increased contact surfaces are gained in addition to the increasing of the same resulting lfrom the arrangement of the cell stated above. The depolarization may he further promoted by the presence of a catalytic substance at-the boundary surface between the electrolyte and the depolarizing gas.

Examples of suitable catalysts are caustic allralie, oxides or hydrcreides of the heavy `metals haring several valencics such as manganese.

ln the n'iai'iufacturin of a cell of fundeinental nature stated above i. e. a cell having a layer, which borders upon the electrolyte and is wet by the same, and a directly subsequent layer not Wet lby the electrolyte (outside which layer, evidently, one or more layers of an arbitrary nature in the respects mentioned above may be pro y'ideali one may, eif'idently proceed in diiierent manners.

Thus, in the manufacturing ot a cell, ac-

-cordingl to this invention one may Wholly or partially use a known, minutely divided shapable mixture, containing chiefly solid organic substances, such as carbon in the state of coke, anthracite etc. and more or less liquid inatters of a more or less fat nature such as tar, if Wanted in combination with other substances such as silicates, Which are able to prevent the electrolyte 'from t'orcinijY its Way ont through the carbon. After the vessel has been shaped in due nianner and', if Wanted, dried, it is heated to suilicient high temperatures tor the procuring of a good conducting cagacity, for instance g500O cent-igrade or more. ln order that the active Walls of the vessel may get the nature stated above, in case of a subi' ance being used, one may proceed, according' to this invention, in such nianner that the niaxiniuni temperature and the period ot heating are so adapted, that the fat substance is not burnt away from the Whole body but onlg7 at its surfaces, a fat layer, not permitting' the electrolyte to permeate, bei. lett at the central zone of the cross sectieof the Wall of the vessel, While v"uch is tree from fat and into which the rolyte penetrate, exists et innne tace of the Wall. The said i thod may modified in such manner, that the fat substance used for the producing of `the material, is burnt away completely or partially "troni V Walls ci the vessel and the latter are then inip nated with tat substance, such parain. fgregation, the solvent, i1 greatestv p, lt,

a suitable state e the evaporating f completelyv or igor at the inner surtac for instance by subjecting ti during a certain period 'to perature higher 1= the itat substance, is supplied by ni solution of sal' and so on), hea

A further that the carbon stance, rsed for rial l ecn bi tiallj.: is imprn its outer side an(`| there side ot the ves lnstcad ci" substance exis side of tin` ye' the electrolyte and consequently prevents the same from penne-ating. The said character may be imparted to the material last mentioned by adding to tac carbon bulk, during the preparing` of saine, consequently previously to the burning' operation, a sub1 T5 stance, such as a silicate or the like, which impart to the material the nature of not being Wet l the electrolyte.

rlhough the invention is applicable inost closely to liquid electrolyte, including in SU this connection electrolytes ot any consist@ ency, Which permits the electrolyte to bc pou ed, also paste like electrolytes may he used, however, with an inferior result. ln the present case cliangeable as Well as un- 8:3 changeable electrolyte may be used, the latter being, however, preferred.

' In 'the 'practical execution of the in.'ention the carbon preferably, is divided into tivo or incre os, in horizontal or Wl vertical direction such manner, that two or more gained, separated by partition Walls. @Wing o 'the cnicnt the cell may be considercd into tivo or more U5 small cells. In c the dividing of the cell into two n" `ti lal section and thus only one li probably Will be necessa' said dividing of the cell the sub-cells in IW series par t qc per unit oi` Weight par if' ot the practically available comparison with an undiyide' i ani-e size, is gained. the said inc in" greater than the 105 amor lt co1` i the dividingT of the electrolyte i 'The fact is that tot each appl'. cell only the cell voltage ini; i' utilized. which exceeds a c lin it. l 1W The foi Ai the invention as an example drawing. in nliicli il Fig'. Q :i plan View section on the line 115 and 5 arc a .side respectively ol' thc 'nich is ,'iaialicloi'ii- 'can is desi@ 13") A The said s. notches mi' such as hooks i over and the top i .edges of the l'lf terribly elastic sul;-

ci divided fig. and lit- :.ll 5 of an insula e paste-board im- 130 Leonesa pregnated in a special manner is provided, litting tightly to the parts. By the said arrangements two compartments are providedin the vessel, each' containing a zinc tected against injurious action of substances leaving the other electrode. Preferably, the zinc electrode is shaped as shown in Fig. 4, the top parts 7, 7 located close to each other, being semicircular, Fig. 5, and, if wanted, connected by soldering or the joints being made tight in any other suitable manner, so that the said parts form together a cylindrical or, it may be, somewhat conical hollow projection, extending through an opening 8 in the cover, Figs. 1 and 2. Owing to the said arrangement the Zinc electrode fits snugly to the cover and besides the said projection, which may be closed by a cork, forms a handle, facilitating the inserting and the removing of the electrode.. T he said projection may be screw threaded or covered with some elastic substance. The object of arranging in the described manner the electrode, which is consumed, is to 'facilitate the renewal of same. The arrangements described above are, evidently, applicable also to undivided vessels. A. zinc electrode, which is provided with a hollow pro jection, made in a single piece and acts in the same manner, may be procured by casting.

At the renewal of the cell the same carbon electrode may be used, only the electrolyte and thc zinc electrode being renewed. The said renewal is easily ei'ectod according to this invention by disengaging the hooks 3, removing the cover, taking out the zinc electrode and pouring oli' the electrolyte, Fresh electrolyte is then poured into the vessel, new zinc electrodes mounted into the. same, the cover located in its place` if nccessai-y together with fresh tightening substanfse, the hooks brought into acting position and the cork inserted. The joints between the edges of the opening 8 and the projections 7 may, it' necessary, be tightened by means of wax, paraiiin or the like. By rendering the projection somewhat conical no such tightening is necessar The bottomL of the vessel, t rough which no air depolarizationl can take place, must not have the character of the carbon described above and may, it' wanted, be made' ffii part may be manufactured separately or the vessel may be made in the ordinary manne and then cut into two parts.

For connection with the conductor, preferably a part of the carbon substance forming the vessel is covered with metal in an electro-chemical or any other manner.

In order to still more-reduce the evaporation of the electrolyte one or preferably two or threecells together are provided with a coating or a casing of such a nature that in spite of the same air is sufficiently admitted to the cell. lf a gas other than air is used as depolariaing medium, the casing etc. evidently must be such, that the said gas does not permeate the walls of the same.

I claim:

l. Galvanic cell with automatic gas depolarization, comprising in combination an` electrolyte, an electropositive electrode, and

an electronegative electrode, said electronegatlve electrode cons1st1ng substantially ot porous carbon and forming a receptacle for said electrolyte and said positive electrode and the boundary Walls of the same comprising two mutually cohering layers both consisting substantially ot carbon, one of said layers which is in contact with the electrolyte being adapted to be wet by the electrolyte, so that the latter may penetrate into the pores of said layer, while the other layer, which is conductor for electricity is impregnated with substances adapted to prevent the electrolyte from penetrating but permit the air to enter therethrough in or- 00 der to act as a depolarizer. v

Q. Galvani@ cell of the kind set forth comprising, in combination, an electrolyte, an electropositive electrode, an electronegative electrode, said negative electrode forming a receptacle for said electrolyte and said' positive electrode, said negative electrode comprising two mutually cohering layers of different materials, the inner layer, which is in contact with the electrolyte, comprising porous carbon and being adapted to be wet by the electrolyte, while the outer layer consists ot an electrically conductive material impermeable to thc electrolyte but permeable to air. i

(alranic cell of the kind set forth comprising, 1n combination, an electrolyte, an elecrropositive electrode, an electronegativc electrinlc. said negative electrode forming a. recept :wie for the electrolyte and said positive. elcctrtnlej said negative electrode comgifrising two layers, the inner layer which is in contact withtlie electrolyte being permeable to theA electrolyte and the outer layer being impermeable to the electrolyte but per- 1 meable to air.

et. Galvanic cell of the kind set forth, comprising, in combination, an electrolyte, an electropositive electrode and an electronegative electrode, said negative electrode, conllo lli

lill

sist-ing substantially of porous carbon and forming a receptacle for the electrolyte and for said positive electrode, the Walls ot the negative electrode comprising two mutually cohering layers, the inner one of said layers, which -is in contact with the electrolyte being adapted to be Wet by the electrolyte so as to permit the same to penetrate into its pores, While the outer layer is impregnated with substances adapted to prevent the electrolyte from penetrating but permit the air to enter therethrough, the contact Zone between said inner and outer layer containing a catalytic substance for depolarization.

Galvanic cell with automatic gas depolarization, comprising, in combination, an electrolyte, an electropositive electrode, and an electronegative electrode, said negative electrode forming a receptacle for the electrolyte and the positive electrode, the sidewalls of said receptacle comprising two mutually cohering layers both consisting sub stantally of carbon, one of said layers, which is in Contact with the electrolyte, being Lactose adapted to be Wet by the electrolyte, so that the latter may penetrate into the pores of said layer, while the other layer being electrically conductive and is impregnated with substances adapted to prevent the electrolyte from penetrating said layer but permit the air to enter therethrough in order to act as a depolarizer.

6. A galvanic cell with automatic gas dcpolarization comprising, in combination, an electrolyte, an electropositive electrode, an electronegative electrode, one of said elcctrodes being exposed to a depolarizing gas at one of its surfaces and to the electrolyte. at another of its surfaces, said electrode being permeable to said gas, said surface in contact with the electrolyte being permeable to the electrolyte and said surface exposed to aicl gas being impermeable to said electroyte.

ln testimony whereof I have aflixed my signature.

IERMAN DOUGLAS NYBERG. 

